Re: [Qemu-devel] [PATCH v2 1/2] hw/net: add support for Allwinner EMAC Fast Ethernet controller

[Juan Quintela <quintela@redhat.com>]

Peter Crosthwaite <peter.crosthwaite@xilinx.com> wrote:

> But is the saved link state meaningful? The fact that net is not
> migrating means that this link_ok migrated variable is potentially
> incoherent with the net layer. E.G. What happens in the following
> case:
>
> Run QEMU
> Link is Good
> Save
>
> Run Again
> Link is bad
> Load
>
> The loaded emulation will have link_ok due to the vmsd load despite
> the link being down in the new net layer environment. It will not
> correct until net-layer activity causes a ->link_state_changed
> callback.
>
> Can this be just solved cleanly by calling the mii_set_link fn (added
> in this patch) always on post load and removing this link_ok state?
> This will mean that guest will see a link state transition immediately
> on load if the link state changes from the saved-machine state to the
> loaded-machine state.

You can do that on post-load, but the problem is that when you run
post-load, the guest is not running yet on destination, so you need to
be careful about what functions do you use.

Later, Juan.